Because of a tight supply, the Allegheny County Health Department will offer H1N1 influenza vaccine only to certain priority groups at four free clinics Saturday.

The clinics, which will run from 10 a.m. to 4 p.m., will be held at Chartiers Valley High School, 50 Thoms Run Road, Collier; McKeesport High School, 1960 Eden Park Blvd., McKeesport; North Allegheny High School, 10375 Perry Highway, McCandless; and the former Reizenstein Middle School (now Pittsburgh Schenley High School), 129 Denniston Ave., East Liberty.

"Because supplies are limited, these clinics will only be providing vaccine at this time to those most vulnerable to the H1N1 influenza virus," said county Health Director Dr. Bruce W. Dixon.

Those groups include:

??? Individuals between the ages of 6 months and 24 years.

??? People who live with or care for children younger than 6 months.

??? Pregnant women.

??? Health care providers and emergency medical services personnel.

??? People 25 to 64 years old with underlying medical conditions including asthma, diabetes, suppressed immune systems, heart disease, kidney disease and neurocognitive or neuromuscular disorders.

H1N1 mostly affects younger people, with more than 70 percent of the reported cases in Pennsylvania involving people under the age of 25, the health department said. People 65 and older are being asked to wait for H1N1 vaccine until supplies increase.

"It makes sense to vaccinate those who are most vulnerable with our limited supply of vaccine because it not only will protect them but also will help slow the spread of H1N1 to others in our community who aren't yet being affected to the same extent," Dr. Dixon said.

The department said both injectable and nasal spray vaccine will be available. Children under 18 must be accompanied by a parent or guardian.

No appointment is necessary.

To keep people moving through the clinics, health officials recommend downloading the vaccination consent form on the Health Department Web site, www.achd.net, and taking the completed form to their clinic. Additional clinics are planned as more vaccine become available. For more information, call 412-687-2243.

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